Thank you @nebulon for solving this issue off-forums. For future reference: problem was caused by the external storage being unmounted after a reboot. Remounting the storage drive (I use a netcup VPS) and then repairing in the Cloudron dashboard solved the problem. Including the mounting in /etc/fstab solved this issue for following updates/reboots.

@fbartels Indeed! I changed the title accordingly.

@nebulon Could https://git.cloudron.io/cloudron/nextcloud-app/issues/61 be related?

The update to 15 is pushed out now. Please report any issues you encounter if that is the case.

I dont see how this can be supported by nextcloud, unless it would scan the authors inbox. Maybe the nextcloud email addon is able to handle this, but you should probably ask nextcloud support about this.

As a first attempt, you could try to restart the box process with systemctl restart box Also maybe look at the system logs, in case there are any hints for errors.

@yylevas No worries! Glad you found the problem. Breaking stuff is the fastest way to learn!

Lets further handle this in the opened issue tracker item.

Have pushed an update that enables this.

You were right. "unbound" was failed. Turns out IPV6 was disabled which was causing "unbound" to fail and in turn causing the issues with resolving domain names in Nextcloud. This is a vanilla install of Ubuntu 16 LTS so I'm not sure what happened. I enabled IPV6 and rebooted and everything started working. Thanks for the tip.